Fixes for 5.6

Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/queue-5.6/bdi-add-a-dev_name-field-to-struct-backing_dev_info.patch b/queue-5.6/bdi-add-a-dev_name-field-to-struct-backing_dev_info.patch
new file mode 100644 (file)
index 0000000..479499f
--- /dev/null
+++ b/queue-5.6/bdi-add-a-dev_name-field-to-struct-backing_dev_info.patch
@@ -0,0 +1,62 @@
+From e598a50997574ec269cb929840825a615c9fdf9b Mon Sep 17 00:00:00 2001
+From: Sasha Levin <sashal@kernel.org>
+Date: Mon, 4 May 2020 14:47:56 +0200
+Subject: bdi: add a ->dev_name field to struct backing_dev_info
+
+From: Christoph Hellwig <hch@lst.de>
+
+[ Upstream commit 6bd87eec23cbc9ed222bed0f5b5b02bf300e9a8d ]
+
+Cache a copy of the name for the life time of the backing_dev_info
+structure so that we can reference it even after unregistering.
+
+Fixes: 68f23b89067f ("memcg: fix a crash in wb_workfn when a device disappears")
+Reported-by: Yufen Yu <yuyufen@huawei.com>
+Signed-off-by: Christoph Hellwig <hch@lst.de>
+Reviewed-by: Jan Kara <jack@suse.cz>
+Reviewed-by: Bart Van Assche <bvanassche@acm.org>
+Signed-off-by: Jens Axboe <axboe@kernel.dk>
+Signed-off-by: Sasha Levin <sashal@kernel.org>
+---
+ include/linux/backing-dev-defs.h | 1 +
+ mm/backing-dev.c                 | 5 +++--
+ 2 files changed, 4 insertions(+), 2 deletions(-)
+
+diff --git a/include/linux/backing-dev-defs.h b/include/linux/backing-dev-defs.h
+index 4fc87dee005ab..2849bdbb3acbe 100644
+--- a/include/linux/backing-dev-defs.h
++++ b/include/linux/backing-dev-defs.h
+@@ -220,6 +220,7 @@ struct backing_dev_info {
+       wait_queue_head_t wb_waitq;
+ 
+       struct device *dev;
++      char dev_name[64];
+       struct device *owner;
+ 
+       struct timer_list laptop_mode_wb_timer;
+diff --git a/mm/backing-dev.c b/mm/backing-dev.c
+index 680e5028d0fc5..3f2480e4c5af3 100644
+--- a/mm/backing-dev.c
++++ b/mm/backing-dev.c
+@@ -938,7 +938,8 @@ int bdi_register_va(struct backing_dev_info *bdi, const char *fmt, va_list args)
+       if (bdi->dev)   /* The driver needs to use separate queues per device */
+               return 0;
+ 
+-      dev = device_create_vargs(bdi_class, NULL, MKDEV(0, 0), bdi, fmt, args);
++      vsnprintf(bdi->dev_name, sizeof(bdi->dev_name), fmt, args);
++      dev = device_create(bdi_class, NULL, MKDEV(0, 0), bdi, bdi->dev_name);
+       if (IS_ERR(dev))
+               return PTR_ERR(dev);
+ 
+@@ -1047,7 +1048,7 @@ const char *bdi_dev_name(struct backing_dev_info *bdi)
+ {
+       if (!bdi || !bdi->dev)
+               return bdi_unknown_name;
+-      return dev_name(bdi->dev);
++      return bdi->dev_name;
+ }
+ EXPORT_SYMBOL_GPL(bdi_dev_name);
+ 
+-- 
+2.20.1
+

diff --git a/queue-5.6/bdi-move-bdi_dev_name-out-of-line.patch b/queue-5.6/bdi-move-bdi_dev_name-out-of-line.patch
new file mode 100644 (file)
index 0000000..2041d80
--- /dev/null
+++ b/queue-5.6/bdi-move-bdi_dev_name-out-of-line.patch
@@ -0,0 +1,74 @@
+From 8145bb5849cd6455b07aac5e220e4ad0f73ddcff Mon Sep 17 00:00:00 2001
+From: Sasha Levin <sashal@kernel.org>
+Date: Mon, 4 May 2020 14:47:54 +0200
+Subject: bdi: move bdi_dev_name out of line
+
+From: Christoph Hellwig <hch@lst.de>
+
+[ Upstream commit eb7ae5e06bb6e6ac6bb86872d27c43ebab92f6b2 ]
+
+bdi_dev_name is not a fast path function, move it out of line.  This
+prepares for using it from modular callers without having to export
+an implementation detail like bdi_unknown_name.
+
+Signed-off-by: Christoph Hellwig <hch@lst.de>
+Reviewed-by: Jan Kara <jack@suse.cz>
+Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+Reviewed-by: Bart Van Assche <bvanassche@acm.org>
+Signed-off-by: Jens Axboe <axboe@kernel.dk>
+Signed-off-by: Sasha Levin <sashal@kernel.org>
+---
+ include/linux/backing-dev.h |  9 +--------
+ mm/backing-dev.c            | 10 +++++++++-
+ 2 files changed, 10 insertions(+), 9 deletions(-)
+
+diff --git a/include/linux/backing-dev.h b/include/linux/backing-dev.h
+index f88197c1ffc2d..c9ad5c3b7b4b2 100644
+--- a/include/linux/backing-dev.h
++++ b/include/linux/backing-dev.h
+@@ -505,13 +505,6 @@ static inline int bdi_rw_congested(struct backing_dev_info *bdi)
+                                 (1 << WB_async_congested));
+ }
+ 
+-extern const char *bdi_unknown_name;
+-
+-static inline const char *bdi_dev_name(struct backing_dev_info *bdi)
+-{
+-      if (!bdi || !bdi->dev)
+-              return bdi_unknown_name;
+-      return dev_name(bdi->dev);
+-}
++const char *bdi_dev_name(struct backing_dev_info *bdi);
+ 
+ #endif        /* _LINUX_BACKING_DEV_H */
+diff --git a/mm/backing-dev.c b/mm/backing-dev.c
+index 62f05f605fb5b..680e5028d0fc5 100644
+--- a/mm/backing-dev.c
++++ b/mm/backing-dev.c
+@@ -21,7 +21,7 @@ struct backing_dev_info noop_backing_dev_info = {
+ EXPORT_SYMBOL_GPL(noop_backing_dev_info);
+ 
+ static struct class *bdi_class;
+-const char *bdi_unknown_name = "(unknown)";
++static const char *bdi_unknown_name = "(unknown)";
+ 
+ /*
+  * bdi_lock protects bdi_tree and updates to bdi_list. bdi_list has RCU
+@@ -1043,6 +1043,14 @@ void bdi_put(struct backing_dev_info *bdi)
+ }
+ EXPORT_SYMBOL(bdi_put);
+ 
++const char *bdi_dev_name(struct backing_dev_info *bdi)
++{
++      if (!bdi || !bdi->dev)
++              return bdi_unknown_name;
++      return dev_name(bdi->dev);
++}
++EXPORT_SYMBOL_GPL(bdi_dev_name);
++
+ static wait_queue_head_t congestion_wqh[2] = {
+               __WAIT_QUEUE_HEAD_INITIALIZER(congestion_wqh[0]),
+               __WAIT_QUEUE_HEAD_INITIALIZER(congestion_wqh[1])
+-- 
+2.20.1
+

diff --git a/queue-5.6/series b/queue-5.6/series
index c8e68384b9a157ab9e3b42a8bf547d551bd52945..bcdd2431fdbf53085f4d7a5e54b9a00337d4bf19 100644 (file)
--- a/queue-5.6/series
+++ b/queue-5.6/series
@@ -112,3 +112,5 @@ iommu-virtio-reverse-arguments-to-list_add.patch
 scripts-decodecode-fix-trapping-instruction-formatting.patch
 mm-memcg-fix-error-return-value-of-mem_cgroup_css_alloc.patch
 kvm-x86-use-kvm-cpu-capabilities-to-determine-cr4-reserved-bits.patch
+bdi-move-bdi_dev_name-out-of-line.patch
+bdi-add-a-dev_name-field-to-struct-backing_dev_info.patch